Chinese algae invades Venice

By Malcolm Moore in Rome

12:01AM BST 24 Jun 2006

A voracious species of Chinese algae is attacking Venice, creating a thick mantle of scum in the city's canals.

Undaria pinnatifida, which grows up to three metres long and often rises as high as half a metre above the waterline, is believed to have reached Venice by clinging on to the hulls of ships from Brittany, in France, where it is grown for use in cosmetic products.

It was reported yesterday to be proving much more of a nuisance than a smaller, native species of algae found in Venice's lagoon, which also pollutes the city's waterways and in summer helps to contribute to its heady odours.

"After clothes, lace and handbags, nobody expected that China would also invade our water in the Gulf of Venice," said the newspaper La Repubblica.

It added that the Chinese algae have "hooks as large as hands" and they "leave no space for other species, wiping the canals clean of all other algae".

The Chinese species is a much darker brown than the native seaweed. It is found throughout the South China Sea. In Japan, where it is called wakame, or "mustard of the sea", the algae is eaten and is highly prized for its high vitamin and mineral content.

Daniel Curiel, a scientist who is observing the algae, said that examples had been spotted in many of the city's main canals, including the basin around St Mark's Square.